125F Interal Case Ambient Temperature

[Clocker]

I was playing around with the fans in my Fong Kai FK-320ATX. In a quest for a quieter PC, I replaced the fan in my Enhance 300W PS with a Panaflo low speed unit. BUt, it provide additional airflow for my system (see below), I had an Enermax Adjustable speed 120mm fan intake up front. I tape up all other air outlets at the back to force more air through the PSU. This set-up worked great. I could maintain an internal case temp of around 90F when running at 100% load for days on end.

I decided to turn off the 120mm unit and the 80mm L1A (at 7V) in front of the drives, and run only a 92mm exhaust fan at 7v just to see what happened. I engaged in a little CS. About 1 hour later, I checked the case them (with MBM). My internal case temp was 125F! I put my hand on the side of the case and it felt hot. I opened her up and felt the side of the drive cage (with my 10K II and X15)...oh my so very very toasty! Never felt a drive get that hot before!

Nonetheless, I turned the 120mm unit back on as well as the 80mm drive(s) fan. and I might shut off the 92mm ehaust to force more air through the PSU again.

I must say I AM impressed with that Swiftech MCX462A cooler though. It maintained a CPU temp of only about 7F over the internal case temp for my AthlonXP 1700.

Now my CPU is happliy chugging along at 125F instead of the inside of my case...and my case temp is a 102F and dropping...

JUst a boring story. But, keep in mind...controlling airflow is not just adding fans. The path you make the air take is just as important as the volume of air you move!

CLocker

 

[Buck]

I must say I AM impressed with that Swiftech MCX462A cooler though. It maintained a CPU temp of only about 7F over the internal case temp for my AthlonXP 1700.

7F? Great gobbs of goose eggs, that is cold. You sure it wasn't 70F?

Either way, your point of airflow is well taken.

And yes, I have felt toasty hot SCSI drives. Pack 5 WD4360 tape-seal drives into a mid-tower running off of two WD SCSI cards. The intermal case temp was so hot, an occassional drive would report as failed in the RAID 5 array. Eventually, I just took the cover off (the case is a Gateway P5-166; with the same processor inside), and fixed two 300mm fans blowing at the drives. All is well, but the temp measures 80F at one inch above the open case.

BR

 

[P5-133XL]

7 degrees above the interior temp 102 + 7 = 109F, 125 + 7=132F

 

[P5-133XL]

I was playing around with the fans in my Fong Kai FK-320ATX. In a quest for a quieter PC, I replaced the fan in my Enhance 300W PS with a Panaflo low speed unit. BUt, it provide additional airflow for my system (see below), I had an Enermax Adjustable speed 120mm fan intake up front. I tape up all other air outlets at the back to force more air through the PSU. This set-up worked great. I could maintain an internal case temp of around 90F when running at 100% load for days on end.

I decided to turn off the 120mm unit and the 80mm L1A (at 7V) in front of the drives, and run only a 92mm exhaust fan at 7v just to see what happened. I engaged in a little CS. About 1 hour later, I checked the case them (with MBM). My internal case temp was 125F! I put my hand on the side of the case and it felt hot. I opened her up and felt the side of the drive cage (with my 10K II and X15)...oh my so very very toasty! Never felt a drive get that hot before!

Nonetheless, I turned the 120mm unit back on as well as the 80mm drive(s) fan. and I might shut off the 92mm ehaust to force more air through the PSU again.

I must say I AM impressed with that Swiftech MCX462A cooler though. It maintained a CPU temp of only about 7F over the internal case temp for my AthlonXP 1700.

Now my CPU is happliy chugging along at 125F instead of the inside of my case...and my case temp is a 102F and dropping...

JUst a boring story. But, keep in mind...controlling airflow is not just adding fans. The path you make the air take is just as important as the volume of air you move!

CLocker

Try switching your 120mm intake fan to an exhaust fan and disabling the 80mm HD coolers and see if that helps. The point is to force all the air to enter via the HD's cooling them. The next issue is to discover if you short circuit the air flow over the CPU and MB by causing the air flow to go directly from HD's to front fan. What is important is ballancing the fans to even out the exhaust and produce air everywhere. Even without ballanced fans, you can solve that problem with an appropiate cardboard baffle that forces the air to take a circuitous route to the front fan. The HD fans serve no point if the only intake holes are through the HD's because all new cold air must come from there regardless of the fans.

Generally it is much easier to analyze air flow by limiting the intakes and only having exaust fans. Ideally you want a transparent case and then use a smoke test to see where the air flows and where it does not.

 

[Clocker]

Mark-

You have a pretty good idea there. The only problem with it that I see is that I feel I NEED positive pressure within my case. The reason being is that I have replaced with PSU fan with a weak quiet one. I'm using the 120mm intake (which is also very quiet) to pressurize the case in order to force (what I consider) an acceptable amount of airflow through the PSU. Also, I've read that running a system with positive internal pressure help to keep the inside of the case cleaner. That seems to be true in my case (no pun intended).

Either way, my cooling was great the way I had it so I'm just going to go back to that (i.e. turn off the 92mm exhaust, tape up the outlets, and force more air up and out through the PSU.

Thanks for taking the time to respond though. I would try that idea if I had a PSU with a normal speed fan...

C

 

[P5-133XL]

My suggestion would be to try it. After all, it probably will be no worse than totally disabling the 120mm and the HD fans. Maybe, you will find it will work better with less noise. You really won't be able to tell until you try it. It is generally very easy to change a fan from intake to exhaust by simply changing the polarity of the DC fan.

The problem with the 120mm intake, is that you are probably limiting the air flow around the HD's because it is easier to enter via the big fan

As far as dust is concerned, there is no difference between a positive presure system, a neutral, or a negative presure system unless there are actual filters on the intake(s). However the air enters, the dust will enter with the air unless prevented via filter. However, if there is fast air-flow throughout the system then the dust may not have a chance of settling out and may be exhausted with the outgoing air. With my carriers, I've simply attached some foam filters, infront of my HD carriers. Occasionally (whenever, I think about it or notice the dust), I detach, clean and re-attach them (using rubber cement).

 

[time]

It is generally very easy to change a fan from intake to exhaust by simply changing the polarity of the DC fan.

Say, what!?

I guess you meant turning the fan around, Mark?

BTW, a positive or neutral pressure system may give the appearance of attracting less dust, provided there is only one intake. That is, it tends to plaster everything around or beyond that inlet, but not elsewhere (obviously). But it's no substitute for a filter.

Surprisingly, a filter can still help even if there are other inlets. Path of least resistance and all that.

 

[P5-133XL]

No I actually meant taking plug of a two pin fan and plugging it in backwards: It works just fine for reversing the direction of the motor. With 3 pin plugs, it is easier to physically move the fan.

Mark Turner

 

[time]

I guess that's okay for diagnostic purposes, but I wouldn't want anyone to get the impression that fans are intentionally bidirectional. The blades are designed to spin in one direction only, not like some ceiling fans.

 

[NRG = mc²]

erm... brushless DC motors such as the ones in your typical PC fan won't work the other way round. Only normal commutator motors will work this way.

 

[Bozo]

I bought some 28cfm centrifical fans at Radio Shack. (the normal case fans are axial) The only noise comming from them is the air movinig. No beating blade noise. They are not much bigger than a 80mm fan. Really nice.
I have two mounted at the top rear of the case where a redundant power supply would go. These are blowing air out of the case. With 4 hard drives, 2 CDs, and a PIII 800 running at 936, the temperature inside the case is the same as the room temperature. This is a server case which has more room inside, so it is probably cooler to start with.

But these centrifical fans are really nice and quiet.

Bozo

 

[NRG = mc²]

You mean those blowers? Those are nice, I have one off a Silverado, Nidec Gamma or something. I made my own system using a rear slot cover that held it up right in front of the memory on my old system and blew the air right at them.